Concurrent Migration of Multiple Pages in software-managed hybrid main memory

This paper describes Concurrent Migration of Multiple Pages (CMMP), a new hardware-software mechanism for managing hybrid main memory (DRAM+PCM). CMMP migrates multiple pages concurrently without significantly affecting the memory bandwidth available to applications. CMMP provides a simple interface for the OS to observe memory access patterns. CMMP reduces PCM-to-DRAM transfer bandwidth by copying blocks on-demand. It also reduces DRAM-to-PCM bandwidth by suppressing the transfer of untouched blocks back to PCM. Compared to a state-of-the-art page migration approach for hybrid memory, CMMP improves performance by 14% and reduces energy consumption by 29% on average.